What is dominant inheritance?

If one of two parents is affected by a genetic condition with a dominant inheritance pattern, every child has a one-in-two chance of being affected. So on average half their children will be affected and half their children will not be affected and so will not pass on the condition. However, as chance determines inheritance, it is also possible that all or none of their children will be affected. Examples of genetic conditions that show a dominant pattern of inheritance are Huntington's disease, achondroplasia and neurofibromatosis.